Fix checkstyle errors when building archetype-generated apps

Checkstyle validation is now enabled by default in onos-dependencies
(archetypes' parent pom). We also add a reference to the archetypes' pom
to disable checkstyle, if needed.

Change-Id: I9b6e6cecf2d704f52ec1f118eae2aafd03cf0b9a
diff --git a/tools/package/archetypes/bundle/src/main/resources/archetype-resources/pom.xml b/tools/package/archetypes/bundle/src/main/resources/archetype-resources/pom.xml
index 08f248b..c996608 100644
--- a/tools/package/archetypes/bundle/src/main/resources/archetype-resources/pom.xml
+++ b/tools/package/archetypes/bundle/src/main/resources/archetype-resources/pom.xml
@@ -84,6 +84,16 @@
                 <groupId>org.onosproject</groupId>
                 <artifactId>onos-maven-plugin</artifactId>
             </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <!-- Uncomment to disable checkstyle validation
+                <configuration>
+                    <skip>true</skip>
+                </configuration>
+                -->
+            </plugin>
         </plugins>
     </build>